Gas turbine temperature control responsive to air and fuel flow, compressor intake and discharge temperature and speed



GAS TURBINE TEMPERA TURE CONTI ROL RESPONSIVE TO AIR AND FUEL FLOW,COMPRESSOR INTAKE AND DISCHARGE TEMPERATURE AND SPEED March 20, 1951 A wORR JR 2,545,703

Filed March 17, 1947 2 Sheets-Sheet l GAS TURBINE TEMPERATURE CONTROLRESPONSIVE TO AIR AND FUEL FLOW, COMPRESSOR INTAKE AND DISCHARGETEMPERATURE AND SPEED March 20, 1.951 A w oRR, JR 2,545,703

Filed March 1'7, 1947 2 Sheets-Sheet 2 PUMP q X 1 i 171/1 7 E Q 37316)?"em JNVENTOR.

i 'atenteel Mar. 20, 1951 Andrew williambl r; Jr., Detroit, Mich,assignor *9 929, e .M- 19 Pe B21 9;

Appliegttton Mareh 17,1947, Seria l Ne. 735,212 1 1 Qla i gns. (cue-t1The object of this invention is mgulate the temperature of the burntpgggincts of combustion in a gas turbine,

.i show di a mati a t e t w rt d term f my inyentign. v Fi 2 hew; a q eler on h send q h shaft ef the ges tmjhin. @Figl? shqws details 91 thegqyeljnqreentrgl.

Inthe drawingfuel enters at 4,0, flew s throngh h gengine d vn tfuelsump 1120; thrbiigh ja peeg gpv r 12? whi h alse .qriven bil-"the eng nhreu hna s f 9; en is 1 .2 e l d b bef n es M S ghjtyen lpy the bevelgears 5,5 iibe eel gea 1.55 w riv n the t emi J56 WlliQ i xnain shaft ofthe gas tunbine. The i uel pump 120 is vdriven .frqliil the shaft 159tby'tjt e' be ie 'imme 1'58 whibh dritgesth z ump sh ft mp. fuel(rejected byfthe gevei'nor 122 @s zieturned ,to the pump up .thxo'nghthe rfetwgn beslseg-e .-.l-2 4. ;[he" fuel same ed tfrom the netedtdthefuel nttanceleading to theventnii b mann 9 cam OQIILeQtiOnVa VQ-AZ-Thepistonfi istpushe tomheleftby then-sprin I50- The Lair pressure.icorreetion hellews ,JM

emcuated andtheontside chamber 112:8, surroundingsbelldws 44,isleennected .through'the pipe as to the impact :tube45fltof :the Pitottuhe'cembina- 1 The ofl flows past the selector cam vcorrection valve #2andth'e'port "43 to the passegefi t which flows to the lowfpfessure tankSlt'x'zvPhielf supplies on" pump with "its regulating fluid. Hence,

when the altitude increases then the valve 42 moves te'the right and theflow'alongpassage deereases,'"17he pisteniM-meves tfo 'the left underthe 'infiuenee of" the spring 190, and the element 53, riding'enthe'camfifl, falls andrelieves the ptessure on the spring 62. servomotbrva'lve6! fails and admits .oil under pressmze .t'othepipe 68 from thepassage-3.4. Pipe 68 is at the-same time nenneeted to the low pres: sureoilthk' 56 th=reugh the p'ipe'id." The piston is thereupon travels-tothe left to decrease the pitch of-' the prefiellefortdldeerease thetern-1- per-ature by meving the tail cone to' the "left. Thisfisaccomplished byieonnecting the p'i'st'onred I30 to thelevei" 2J2-"m0unted ion thepix/tot 2M. The'lever 2 I2-i' s .cohneetedthrough thelink 216 te the 1ever" 21'8."'-"-The lever ZIEHS' conneetee'l "to theshaft 220" ';Jjn whieh" is=mounted the lever 222 whihjc'entz ols' thefidsitiqniofthe cone-12. A n inferease' -in sir-w etiternati'cwllyeauses' a decrease n t mperature?" "Meanwhilefl-theairflow responsivemeans are functioning. These means are bellows M, the insiae er fwhichfis eonneeted' to theirn-paet tube V The lelitside eheir n Ier IG iscb'nneetedwt'e the Pitot static tube 5 2 hrough the valile 1B which isthe air temperature" enfection ve;1ve', and

tm oegrithefia sege sz; 'A i estrictietf gb" isiocated in a returnpassage 81 WhiCH-fnderi =the V a1 V e T8 efieeti'v'e t0 @Ontrol thepressgre in chamber 16 with'the te-rjnperature. The Va Ii e' I8 'j 's"beh neted =te -ithefbel levvs" 8 2' and iseo rlihe'te d through 'thep ire$6 to the temperateri'efresponsitze btfl I fiflllo ealtdin theeiii'entfanee A h h. tem ra the v et? $s h the'Pitottiihecb "neti qnfifl- 5-2'is'lesjs efiective. lilew'is fthe r'dgl fi'z descendsinerees'e. fIhe pxiessji ie in-eharnber 38 "is" the pl essiireddytnstfhffrih tl'ie tizilve The pre sure in the' chamber 1 68, abovethe diaphragm H38, is' theconstamt p1=ess1ireiereetedhy th'e'ipzim'p 30.Hence, an increase in airflow causes the servomotor valve 64 to rise.The result of this is that the cone I2 moves to the right or thepropeller pitch is increased as the case may be. The chamber 98, belowthe diaphragm I00, is connected to the chamber I62, below the diaphragm9I, through the restriction I64. The chamber I68, above the diaphragmI00, is connected with the chamber I66, above the diaphragm 91, throughthe restriction I10. The restrictions I'I0I64 render the movement of theconstant differential valve effective to accomplish this desired result,that is to balance air flow against fuel flow.

The fuel flow recording valve 24, when it moves to the left in responseto increased fuel flow decreases the oil flow and causes the pressure inchamber 98 to fall as valve 24 cuts off the admission of high pressureoil from the passage 32, to the chamber 98.

Hence, an increase in air flow causes the pressure in chamber 98 toincrease and the pressure in chamber 98 to decrease with an increase infuel flow. The diaphragm I thus responds to the relative excess of airover fuel flow or excess of fuel over air flow as the case may be.

The temperature of the air delivered by the compressor I02 to thecombustion chamber I6 is measured by the bulb I04. The bulb I04 controlsthe expansion and contraction of the bellows I06. Bellows I06 controlsthe valve I08. Valve I08, when the element I04 is cold, is wide open andthe pressure in passage 32 is transmitted past the valve I08 to thechamber IIO, practically undiminished, through the passage I9I. Thechamber 56 communicates with the chamber H8 through the restriction I72.Chamber II2, above the diaphragm I I4, is in free communication at alltimes with the pressure in the passage 32 on the high pressure side ofthe pump 30 so that at low temperature the diaphragm II4 has littlefunction. It functions at high temperature to assist the diaphragm I00,as the temperature of the gases entering the gas turbine H6 is the sumof the temperature recorded by element I04 plus the temperature rise dueto the fuel/air ratio of the mixture which burns in the combustionchamber I6.

To limit the pressure that can be generated by the pump 30 the pressurerelief valve I32 is provided. Valve I32 is loaded by a spring I34 and iscarried by diaphragm I33.

Cam surface 60 is contoured. The lever I40 permits the surface 60 to berotated about the axis of the piston 38 to present a new surface to thecam follower 58.

The altitude bellows 44 engages with a rod I82 which carries the valve42. The end of the rod I82 engages with the diaphragm I84. A rod I86engages with the other side of the diaphragm I84. The rod I86 is hollowand carries the valve I'M, which valve communicates through a port I16with the passage I80 which is in communication with the restrictedpassage I8, in the throat of the venturi I2, and also communicates withthe chamber 20 surrounding the bellows 22.

The diaphragm I92, located above the rod I93, which rod I93 engages withthe rod. I96 which engages with the top of the servomotor valve 64. Thepressure in the pipe 86 is transmitted to the upper surface of thediaphragm I92 through the pipe I94. Pipe I96 transmits the pressure tothe underside of the diaphragm I92. The pressure transmitted through thepipe I96 is derived from theleft hand side of piston I98 which iscarried by the left hand end of the piston rod I38. A restriction 200,in the piston I98, has the effect of checking the motion of theservomotor valve 84 and thus prevents hunting.

The chamber forming the left hand side of diaphragm I84 is connectedwith the passage 54 through a restriction. The chamber forming the righthand side of the diaphragm I84 is a drain passage ZIIl which drains tothe atmosphere. The chamber 208, at the extreme right of the rod I86,contains a spring 299 which pushes the rod I08 against the diaphragmI84. The chamber 208 is connected to the drain passage 2 I8 through apassage 206.

For a given position of the manually operated lever I40 it is possiblewith valve 42 to vary the temperature automatically, without moving thelever I48, as the altitude increases. At very high altitude valve 42closes and this detail thereupon becomes inoperative above a certainceiling. The action at low altitudes, near sea level, is to lowermaximum temperatures.

The valve I14 maintains the desired fuel/air ratio despite the drop indensity of the air at altitudes, which otherwise would result in aricher mixture.

OPERATION Let us assume that the device is in operation and that thelever I40 has been moved to give a desired temperature in the combustionchamber. The cam follower 58 then rides on the cam 68 and positions theservomotor valve 64, by reason of the spring 62, balancing the pressuresacting down on the diaphragm I00 plus the pressure acting down on thediaphragm H4. The pressure acting on the diaphragm H4 is a pressurewhich is controlled by the temperature downstream from the compressorI02, that is to say, the pressure controlled by the compressortemperature control valve I88. This temperature heats the bulb I04. Heaton the bulb I04 expands the bellows I08. Expansion of the bellows I06causes the valve I08 to descend. The descent of the Valve I88 restrictsthe flow of oil under pressure down the pasage 32, up through the centerof the valve I08, down the passage I'9I into the chamber III! and thenthrough the restriction I72 into the low pressure oil chamber 56, sothat an increase in temperature causes an increased pressuredifferential to act on the diaphragm II4. An increased pressuredifferential acting on the diaphragm II4 causes the servomotor valve 64to descend. This causes the high pressure oil in passage 32 and 34 toact on the right hand side of the piston I0, through the pipe 68 causingthe link I30 to move to the left which causes the cone I2 to open, thatis to move to the left, which permits an increased air flow and therebyreduces the temperature. A similar result is obtained by decreasing thepitch of the propeller driven by the shaft I56. An increase in thepressure differential acting on the diaphragm I has the same effect asan increase in pressure differential acting on the diaphragm H4. Thepressure differential acting on the diaphragm I00 is controlled by thefuel flow acting through the valve 24 and to the air flow acting throughthe valve 84. An increase in fuel flow causes the valve 24 to move tothe left and it decreases the pressure below the diaphragm I08. Anincrease in air flow causes the valve 96 to descend which increases thepressure in chamber I62. ,An increase in pressure in chamber I62decreasesthe chamber to rises, hence,- servomotor valve 64 rises and thecone 12 moves to the right.

'vaive T8 is the temperature correcting valve and corrects for thetemperature in the air en'- trance 90 as recorded in the bulb 88 throughthe pipe 86 and eeuows 84-.-

Whenever the piston It moves to the right or 1e'ft the diaphragm m2checks the movementoi the servomotor valve 54 and hunting is therebyavoided.

The drawing shows a construction in which, the fuel new is excessive,the cone 12 moved to the left when the piston 10 is moved to the left.Alternatively the pitch of a propeller, mounted on the shaft I56, shouldbe decreased when the piston H! is moved to the left. 7 In either casethe ratio of fuel to air is restored to that ratio of fuel to air whichwill give the dc si d r i'se temperature in the combustion chamber [5. aIf the position of the cone i2 is fixed or if the pitch of the propelleris fixed then the move ine'nt of the piston iii, to the left, must be arranged to throttle the flow "of fuel through the fuel venturi [2.

When the second alternative is used, that is, when the Iposition of thecome 12 is fixed or a fixed I'propeller is used on the shaft 156 and thetemperature rise is controlled directly by throbtling the fuel nowthrough the venturi l2, then the "governor I22 has normally no functionand can be set so that it will only act at excessive speeds.

What I claim is:

l. A combustion chamber temperature control device for a gas turbinehaving a turbine driven air compressor, a speed governor driven by saidgas turbineadapted to regulate the speed of said turbine by reducing thefuel supply comprising, temperature responsive means responsive to thetemperature of the air entering the combustion chamber, means responsiveto both the fuel and air flows acting in opposition to each other toproduce a force, said force acting in conjunction with the force derivedfrom-said temperature responsive means to produce a resultant force, aservomotor valve, yieldable means engaging with said servomotor valveacting in opposition to said resultant force, an increase in temperatureof the entering air having the same effect as an increase in fuel flowrelative to air flow to increase said resultant force, a motor, a supplyof fluid under pressure adapted to operate said motor, said servomotorvalve being connected to said pressure fluid so as to control saidmotor, means to vary the air flow through said gas turbine, linkageconnecting said air flow control means with said motor whereby the airsupply is increased with an increase of temperature of the air enteringthe combustion chamber and also by an increase in the fuel flow relativeto the air flow.

2. A device as set forth in claim 1 in which there are additionaltemperature responsive means responsive to the temperature of the airentering said air compressor, said means being associated with the airflow responsive means to render the air flow responsive means lesseffective to oppose the fuel flow responsive means when the air enteringthe compressor is hot.

3. A combustion chamber temperature control device for a gas turbinehaving a speed governor driven by said gas turbine adapted to regulatethe speed of said turbine by reducing the fuel supply, an ai compressordriven by said gas turbinaan air entrance to the compressor, air flowindicating means in said air entrance, air temperature correction meanstherefor, a combustion chamber, an air entrance thereto forming the airexit from said compressor, air temerature responsive means in said exit,a burner in said combustion chamber, a fuel supply therefor, a fuelpassage leading to said burners from said supply, a restriction in saidpassage, load control means for said gas turbine, automatic controlmeans connected to said load control means comprising a hydraulic motor,a source of hydraulic fluid under pressure for said motor, a servomotorvalve for said fluid controlling said motor, yieldable means for movingsaid servomotor valve in the direction to call for more load, meansresponsive to the drop in pressure at said fuel restriction to opposesaid movement, means responsive to an increase in temperature of the airsaid compression exit to also oppose said movement, means responsive toan increase in pressure difference at said air indicating means toassist said movement whereby an increase in fuel flow, a decrease in theair flow and an increase in temperature of the air in the compressorexit jointly act to reduce the load and thereby increase the turbinespeed above the governed speed and to thus reduce the fuel flow andhence the combustion chamber temperature.

4. A device as setforth in claim 3 in which there is a barometric meansadapted to vary said yieldable means so as to correct for the pressuredrop at altitude.

'5. A combustion chamber temperature control device for :a gas turbinehaving :a speed governor driven by :said {gas turbine adapted to limitthe speed of said gas turbine reducing the fuel supply, an aircompressor driven by :said gas turbine adapted to supply said combustionchamber with compressed air, anairentrance to said compressor, air flowindicating means in said :air entrance therefor, an air-exit from saidcompressor, air temperature responsive means :in :said air exit chamber,a burner in said combustion chamber, a fuel supply therefor, a fuelpassage leading to said burner from said fuel :supply, a restriction insaid fuel passage, load control means for said gas turbine, automaticcontrol means therefor comprising a source of hydraulic fluid under con-.stant pressure, an hydraulic motor, a servomotor valve for said motor,manually variable yieldable means for moving said servomotor valve so asto vary the load in said gas turbine, hydraulic means to oppose saidyieldable means so as to position said servomotor valve, said hydraulicmeans being responsive to the drop in pressure at said fuel restrictionacting in opposition to the pressure difference at said air flowindicating means and to the temperature responsive means located in theexit from said air compressor whereby the temperature rise in thecombustion chamber is controlled by the variable yieldable passageleading to'said nozzle, a restriction in said fuel supply passage, asecond control means responsive to the dropin pressure at said fuelrestriction, a speed governor for said gas tur bine driven by said gasturbine, a fuel return passage connected upstream above said fuelrestriction and to the suction side of said fuel pump, said governorbeing adapted to control the flow through said return fuel passage so asto limit the maximum speed of said gas turbine by limiting the fuelflow, load control means for said gas turbine, a source of hydraulicfluid under pressure, hydraulic control mechanism operated therebyincluding a motor and a servomotor valve therefor, yieldable means formoving said servomotor valve so as to increase the load, said secondmentioned control means acting to oppose both said first mentionedcontrol means and said yieldable means, acting jointly, whereby anincrease in fuel fiow relative to air flow reduces the load and thusincreases the speed which causes the governor to reduce the fuel flow.

7. A device as set forth in claim 6 in which there is a third controlmeans responsive to the temperature of the compressed air leading saidair compressor, said third control means acting jointly with said secondcontrol means to oppose said first control means.

8. A device as set forth in claim 6 in which there is an additionalcontrol means responsive to the pressure of the air entering the aircornpressor, said additional means acting so that a fall in pressurereduces the yieldable means and the load.

9. A device as set forth in claim 6 in which there are additionalcontrol means responsive to the pressure of the air entering the aircompres sor and to the temperature of the air compressor air leavingsaid air compressor, both of said means acting to reduce the load as thetemperature rises and the pressure falls.

10. A device as set forth in claim 6 in which there is an additionalcontrol means responsive to the pressure of the air entering the aircompressor adapted to both vary the yieldable means controlling theposition of the servomotor valve and to vary the effect of the drop infuel pressure at said fuel restriction so that the fuel/ air ratio iscorrected for a drop in air pressure of the atmosphere and the yieldablemeans is reduced and the gas turbine load is reduced as the pressure ofthe atmosphere drops.

11. A fuel control mechanism for an external combustion engine includinga gas turbine, a turbine driven air compressor supplying compressed airto a combustion chamber, an air conduit leading to said air compressor,a first control means responsive to variation in the quantity'of airflowing through said conduit, a second control means responsive to thetemperature of the compressed air entering the combustion chamber, afuel nozzle discharging into said combustion chamber, a fuel supplypump, a fuel supply passage leading to said nozzle, a restriction insaid fuel supply passage, a third control means responsive to the dropin pressure in said fuel restriction, automatic means for controllingthe fuel/air ratio, comprising a source of hydraulic fluid underpressure, hydraulic control mechanism operated thereby including a motorand a servomotor valve therefor, manually selected means for moving saidservomotor valve so as to decrease the fuel supply, said second andthird mentioned control means acting jointly to oppose both said firstmentioned control and said yieldable means, acting jointly, whereby anincrease in the fuel/air ratio is automatically reduced whenever the sumof the temperature of the air entering the combustion chamber plus afunction of the fuel/air ratio exceeds the value of theselectedyieldable means.

ANDREW WILLIAM: ORR, JR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,011,420 Samuelson Aug. 13, 19352,378,036 Reggio June 12, 1945 2,384,282 Chandler Sept. 4, 19452,405,888 Holley Aug. 13,1946

